1. Field of the Invention
The present invention generally relates to the forming of an electronic shooting system—photographic camera or video camera—with a variable focal length to obtain a focusing or a zoom effect.
2. Description of the Related Art
Generally, an electronic photographic or video camera comprises a semiconductor chip on which are formed a network of optical sensors and, possibly, associated processing circuits. A lens or, more generally, an optical objective having its axis corresponding to an axis orthogonal to the center of the optical sensor network is arranged in front of the chip.
The present invention more specifically relates to a variable-focal-length optical system, that is, a system in which the plane of the objective may be displaced in the direction of the optical axis, parallel to the sensor plane. For this purpose, the objective assembly comprises a motor for shifting the objective along the optical axis. This motor is an electric motor which is controlled by circuits which are associated with the sensor chip or which are arranged on another chip assembled on the same support as the sensor chip. This support generally is a plate of printed circuit board type. An electric connection between pads on this printed circuit board and connection terminals of the motor must then be provided.
The various known solutions to assemble a variable-focus shooting system are relatively heavy-duty and all exhibit various disadvantages.
In certain conventional solutions, the motor connectors are connected to the pads on the optical card by a flexible connection, which implies relatively high costs due to its requiring weldings. Further, such weldings generally are a source of weakness of the electric system.
In certain conventional solutions, the lens mount is glued on the support (the printed circuit board) of the sensor. However, since this gluing must be performed so that the optical axis of the objective and the axis perpendicular to the center of the sensor chip are confounded, complex means, expensive and long to use, of relative XY positioning of the sensor chip and of the objective mount must be provided.